Definition
An engagement score is a numerical value assigned to each subscriber that represents their overall level of interaction with your email programme. Scores are typically on a 0-100 scale, with 100 being the most engaged and 0 being completely disengaged. The score is calculated by combining multiple engagement signals into a weighted formula.
Email service providers and deliverability platforms use engagement scores to determine which subscribers receive emails, how frequently, and how the mailbox providers view your sending reputation. Subscribers with high engagement scores improve your overall sender reputation, while low-scoring subscribers drag it down and may need to be sunset.
Typical Components of an Engagement Score
| Signal | Typical Weight | Description |
|---|---|---|
| Opens (recency-weighted) | 25-35% | Recent opens weighted higher than historical opens |
| Clicks (recency-weighted) | 20-30% | Recent clicks weighted higher than historical clicks |
| Replies | 15-20% | Direct replies are strong positive signals |
| Unsubscribes | -10-20% | Strong negative signal that indicates disengagement |
| Spam complaints | -20-30% | The strongest negative signal |
| Recency of any engagement | 10-15% | How recently the subscriber last engaged |
| List lifecycle stage | 5-10% | New subscribers start with a baseline score |
How ESPs Use Engagement Scores
| Use Case | Description |
|---|---|
| Send frequency management | Reduce sending to low-scoring subscribers to protect deliverability |
| Sunset policy triggers | Automatically remove subscribers whose score drops below a threshold for a set period |
| Segmentation | Create engaged segments (score 50+) for re-engagement campaigns |
| Priority inbox placement | High-scoring subscribers may receive preferential inbox placement |
| A/B test targeting | Include only high-scoring subscribers for statistically significant tests |
| List health monitoring | Track average engagement score over time as a leading indicator of deliverability |
How to Build an Engagement Scoring Model
- Define the scoring range: A 0-100 scale is standard. Set a baseline score for new subscribers (typically 50-60). Increase or decrease based on engagement events.
- Weight recency heavily: A click yesterday is worth significantly more than a click six months ago. Use a decay function where engagement events lose value over time (e.g., 10% decay per week).
- Assign points for positive actions: An open could be worth +1 to +5 points depending on recency. A click could be +5 to +10. A reply could be +10 to +20. Negative actions (unsubscribe, complaint) should deduct heavily.
- Set floor and ceiling values: Maintain the 0-100 range by clamping values. A subscriber cannot score below 0 or above 100 regardless of their cumulative events.
- Include engagement recency score: Add a component that measures how recently any engagement occurred. A subscriber who engaged yesterday scores higher than one who last engaged six months ago, even if they have similar event counts.
- Test and iterate: Start with a simple model and refine based on how well it predicts spam complaints, unsubscribes, and conversions. The best engagement score is one that correlates strongly with your business outcomes.
Related Glossary Terms
A/B Testing
A/B testing in email marketing is the practice of sending two variations of an email to a small sample of your list to determine which version performs better before sending the winner to the remaining subscribers.
Abandoned Cart Email
An abandoned cart email is an automated message sent to customers who added items to their online shopping cart but left without completing the purchase. It is one of the highest-converting email types in ecommerce.
AMP for Email
AMP for Email is a Google-developed framework that allows email messages to include interactive elements like forms, carousels, accordions, and live content. It turns static emails into dynamic, interactive experiences directly inside the inbox.
Bounce Rate
Email bounce rate is the percentage of emails that were rejected by the receiving server before reaching the recipient. It is a key indicator of list health and data quality.
CAN-SPAM Act
The CAN-SPAM Act is a US law that sets rules for commercial email. It requires accurate subject lines, a physical address, a clear opt-out mechanism, and prompt processing of unsubscribes. Violations can result in penalties up to $51,744 per email.
Click-Through Rate
Click-through rate (CTR) is the percentage of email recipients who clicked one or more links in your email campaign. It measures how compelling your content and call-to-action are.
Frequently Asked Questions
A score of 50 or above is typically considered good, indicating active and recent engagement. Scores of 70+ indicate highly engaged, valuable subscribers. Scores below 30 indicate at-risk subscribers who should be placed into re-engagement campaigns or sunset workflows. The exact thresholds depend on your scoring model.
Engagement scores should update in real time or near-real time when engagement events occur. A subscriber who opens a campaign today should immediately reflect that engagement in their score. Daily batch updates are acceptable for most programmes, but more frequent updates enable faster response to engagement changes.
Most major ESPs (Klaviyo, HubSpot, Mailchimp, Salesforce Marketing Cloud) include some form of engagement scoring. The quality and customisation vary. Klaviyo and HubSpot offer more sophisticated scoring with customisable weights. Smaller ESPs may offer simpler recency-based scoring or no built-in scoring at all.
Yes. A declining engagement score is one of the strongest predictors of subscriber churn. Subscribers whose scores drop by 20+ points over a 30-day period have a significantly higher probability of unsubscribing or filing a spam complaint within the next 60 days. Monitor score trends, not just absolute values.
Not immediately, but you should move them into a re-engagement sequence. If a subscriber's score stays below a threshold (e.g., 20) after a 3-5 email re-engagement campaign, they should be sunset and removed from your active list. Continuing to send to very low-scoring subscribers damages your overall sender reputation and deliverability.